334 lines
10 KiB
Java
334 lines
10 KiB
Java
/* SortingFocusTraversalPolicy.java --
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Copyright (C) 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package javax.swing;
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import java.awt.Component;
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import java.awt.Container;
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import java.util.Comparator;
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import java.util.Iterator;
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import java.util.TreeSet;
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/**
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* @author Graydon Hoare
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* @author Michael Koch
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*
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* @since 1.4
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*/
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public class SortingFocusTraversalPolicy
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extends InternalFrameFocusTraversalPolicy
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{
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/**
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* The comparator used to sort elements in the focus traversal cycle
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* managed by this class.
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*/
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Comparator comparator;
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/**
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* <p>Whether or not to perform an "implicit DownCycle" when selecting
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* successor components within a focus cycle.</p>
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*
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* <p>When this is true, requesting the "next" component following a
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* component which is a focus cycle root (and, necessarily, a container)
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* will enter the focus cycle root of that container, and return its
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* default focus.</p>
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*
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* <p>When this property is false, requesting the "next" component will
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* simply advance within the containing focus cycle, subject to the
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* {@link #comparator} order and the {@link #accept} judgment.</p>
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*
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* @see #getImplicitDownCycleTraversal()
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*/
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boolean implicitDownCycleTraversal = true;
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/**
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* Creates a new <code>SortingFocusTraversalPolicy</code> with no
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* comparator set.
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*/
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protected SortingFocusTraversalPolicy()
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{
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// Do nothing here.
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}
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/**
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* Creates a new <code>SortingFocusTraversalPolicy</code> with the given
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* comparator set.
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*
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* @param comparator the comparator to set
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*/
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public SortingFocusTraversalPolicy(Comparator<? super Component> comparator)
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{
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this.comparator = comparator;
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}
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/**
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* Decide whether a component is an acceptable focus owner.
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*
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* @param comp The component which is a candidate for focus ownership.
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*
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* @return true if the component is focusable, displayable, visible, and
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* enabled; otherwise false
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*/
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protected boolean accept(Component comp)
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{
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return (comp.isVisible()
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&& comp.isDisplayable()
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&& comp.isEnabled()
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&& comp.isFocusable());
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}
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/**
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* Get the current value of the {@link #comparator} property.
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*
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* @return the current value of the property
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*
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* @see #setComparator
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*/
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protected Comparator<? super Component> getComparator()
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{
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return comparator;
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}
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/**
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* Set the current value of the {@link #comparator} property.
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*
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* @param comparator the new value of the property
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*
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* @see #getComparator
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*/
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protected void setComparator(Comparator<? super Component> comparator)
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{
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this.comparator = comparator;
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}
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private TreeSet getSortedCycle(Container root, TreeSet set)
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{
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if (set == null)
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set = (getComparator() == null
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? new TreeSet()
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: new TreeSet(getComparator()));
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if (root != null)
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{
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Component[] comps = root.getComponents();
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for (int i = 0; i < comps.length; ++i)
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{
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Component c = comps[i];
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if (accept(c))
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set.add(c);
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if (c instanceof Container)
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getSortedCycle((Container) c, set);
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}
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}
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return set;
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}
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/**
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* Return the component which follows the specified component in this
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* focus cycle, relative to the order imposed by {@link
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* #comparator}. Candidate components are only considered if they are
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* accepted by the {@link #accept} method.
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*
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* If {@link #getImplicitDownCycleTraversal} is <code>true</code> and the
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* <code>comp</code> is a focus cycle root, an "implicit DownCycle"
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* occurs and the method returns the
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* <code>getDefaultComponent(comp)</code>.
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*
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* @param root the focus cycle root to search for a successor within
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* @param comp the component to search for the successor of
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*
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* @return the component following the specified component under
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* the specified root, or null if no such component is found
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*
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* @throws IllegalArgumentException if either argument is null, or
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* if the root is not a focus cycle root of the component
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*/
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public Component getComponentAfter(Container root,
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Component comp)
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{
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if (comp == null || root == null || !comp.isFocusCycleRoot(root))
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throw new IllegalArgumentException();
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if (getImplicitDownCycleTraversal()
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&& comp instanceof Container
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&& ((Container)comp).isFocusCycleRoot())
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{
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return getDefaultComponent((Container) comp);
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}
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TreeSet set = getSortedCycle(root, null);
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Iterator i = set.iterator();
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while (i.hasNext())
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{
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Component c = (Component) i.next();
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if (c != null && c.equals(comp))
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{
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if (i.hasNext())
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return (Component) i.next();
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break;
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}
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}
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return null;
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}
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/**
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* Return the component which precedes the specified component in this
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* focus cycle, relative to the order imposed by {@link
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* #comparator}. Candidate components are only considered if they are
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* accepted by the {@link #accept} method.
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*
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* @param root the focus cycle root to search for a predecessor within
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* @param comp the component to search for the predecessor of
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*
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* @return the component preceding the specified component under the
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* specified root, or null if no such component is found
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*
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* @throws IllegalArgumentException if either argument is null, or
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* if the root is not a focus cycle root of the component
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*/
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public Component getComponentBefore(Container root,
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Component comp)
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{
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if (comp == null || root == null || !comp.isFocusCycleRoot(root))
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throw new IllegalArgumentException();
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TreeSet set = getSortedCycle(root, null);
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Iterator i = set.iterator();
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Component prev = null;
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while (i.hasNext())
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{
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Component c = (Component) i.next();
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if (c != null && c.equals(comp))
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break;
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prev = c;
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}
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return prev;
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}
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/**
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* Return the default component of <code>root</code>, which is by default
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* the same as the first component, returned by {@link
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* #getFirstComponent}.
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*
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* @param root the focus cycle root to return the default component of
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*
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* @return the default focus component for <code>root</code>
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*
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* @throws IllegalArgumentException if root is null
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*/
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public Component getDefaultComponent(Container root)
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{
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return getFirstComponent(root);
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}
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/**
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* Return the first focusable component of the focus cycle root
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* <code>comp</code> under the ordering imposed by the {@link
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* #comparator} property. Candidate components are only considered if
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* they are accepted by the {@link #accept} method.
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*
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* @param root the focus cycle root to search for the first component of
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*
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* @return the first component under <code>root</code>, or null if
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* no components are found.
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*
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* @throws IllegalArgumentException if root is null
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*/
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public Component getFirstComponent(Container root)
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{
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if (root == null)
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throw new IllegalArgumentException();
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TreeSet set = getSortedCycle(root, null);
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Iterator i = set.iterator();
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if (i.hasNext())
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return (Component) i.next();
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return null;
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}
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/**
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* Return the last focusable component of the focus cycle root
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* <code>comp</code> under the ordering imposed by the {@link
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* #comparator} property. Candidate components are only considered if
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* they are accepted by the {@link #accept} method.
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*
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* @param root the focus cycle root to search for the last component of
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*
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* @return the last component under <code>root</code>, or null if
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* no components are found.
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*
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* @throws IllegalArgumentException if root is null
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*/
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public Component getLastComponent(Container root)
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{
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if (root == null)
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throw new IllegalArgumentException();
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TreeSet set = getSortedCycle(root, null);
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Iterator i = set.iterator();
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Component last = null;
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while (i.hasNext())
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last = (Component) i.next();
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return last;
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}
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/**
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* Return the current value of the {@link #implicitDownCycleTraversal}
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* property.
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*
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* @return the current value of the property
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*
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* @see #setImplicitDownCycleTraversal
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*/
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public boolean getImplicitDownCycleTraversal()
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{
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return implicitDownCycleTraversal;
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}
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/**
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* Set the current value of the {@link #implicitDownCycleTraversal}
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* property.
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*
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* @param down the new value of the property
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*
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* @see #getImplicitDownCycleTraversal
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*/
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public void setImplicitDownCycleTraversal(boolean down)
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{
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implicitDownCycleTraversal = down;
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}
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}
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